<div class="row">
    <div class="col-md-6 col-md-offset-3">
        <div class="panel panel-default">
            <div class="panel-heading">
                <h3 class="panel-title">注册</h3>
            </div>
            <div class="panel-body">
                <form>
                    <div class="form-group">
                        <input type="text" class="form-control" id="exampleInputEmail1" placeholder="用户名" name="user_name">
                    </div>
                    <div class="form-group">
                        <input type="password" class="form-control" placeholder="密码" name="password" />
                    </div>
                    <div class="form-group">
                        <input type="password" class="form-control" placeholder="重复密码" name="password" />
                    </div>
                    <button type="submit" class="btn btn-default">注册</button>
                </form>
            </div>
        </div>
    </div>
</div>